Unless I'm reading that map wrong, Alabama was slightly below average. Also Georgia is pretty close to the middle for average income, and once you adjust for cost of living it's even higher.
It's interesting that the difference between Georgia and Alabama is so great, because once you remove metro Atlanta, the weather, culture, income, and cost of living are pretty close. So why does it seem someone living in rural GA is much happier than someone living in rural Alabama? By the way I live in Georgia, but only about 30 minutes from the Alabama line.